A Gift of Sin
by Adora Dark
Summary: The night of Gou's 18th birthday spent with Sousuke and Rin in a fateful party of three. Sousuke x Gou x Rin WARNINGS: F/M/M, incest references, yaoi


**A Gift of Sin**

A small gust of wind cruised through midnight , making the hem of Gou's silky robe timidly quiver in the air. She let the ruby garment slide off her body and fall gently on the tiled floor , exposing her alabaster skin to the silver moonglow and the sapphire in his eyes. Holding a glass of the finest champagne in her right hand, Gou carefully lowered herself in the crystal water. Leisurely leaning against the pool's wall, with his muscular arms resting on the edge, Sousuke let his lazy gaze follow her closely. A soft disturbance gradually spread across the pool's waters , as she graciously swam towards him, her delicate strokes leaving wrinkles on the azure surface.

"Perhaps I should arrest you for over-drinking tonight". Only he could elicit such a stern tone while keeping a relaxed face.

"Think twice, Sousuke-kun!" Gou scooted next to him , a beaming smile illuminating her features. "As of tonight, I am an adult as well and can drink alcohol as much as my heart pleases. So, what you'll arrest me for?"

"I'm sure I can find one thing or two."

A jumble of sounds and curses interrupted the teasing moment , as Rin's angry voice echoed throughout the villa. He was furiously pacing along the wide glass of the well lit living room, which led to the verdant terrace and its luxurious swimming pool. Clenching a cellphone next to his ear, he kept gesturing in the air, consumed by his vivid conversation and compelling as always.

"Well, it looks like you aren't the only one who will need another drink soon."

"Onii-chan..."

Sousuke folded an arm behind his head , causing his vigorous biceps to stand out. He leaned back and let his eyes sail along the nocturnal sky, a hint of smugness tickling his aloof demeanor. It had been a warm night full of surprises and it was coming close to turn reckless. Gou's sigh made him cast a checking glance at her. Her loose locks flowed into a burgundy cascade down her bare back , their ends vanishing into the water. Her usual ponytail was long gone at some point between her earlier, carefree dance and the empty champagne bottles. Two perfectly shaped pearl mounds, clad in a strawberry bikini top, kept slowly rising above the blue surface with every breath she was taking , before disappearing again from his view. It perplexed him how innocent Gou could really be at times like this, totally oblivious to their proximity or the tantalizing sight their naked bodies were offering. Her focus seemed completely directed to Rin and the loud performance he was delivering behind the glass.

"Nice swimsuit"

Whatever chain of worries was irking her mind broke instantly, as Gou turned back to Sousuke with her face brightening up anew.

"Thanks Sousuke-kun! It's one of onii-chan's gifts for tonight. There's even a little shark ornament where the straps are tied together at the nape. I like how.."

"So if I pull that shark" he stretched his hand and gently pushed aside her red mane, revealing her milk-white nape "this top will come undone and float on the water?"

"Sousuke-kun, dont!"

"Why not?" His voice was low, as his long fingers grazed the straps of her thin top. Gou's eyes widened. Shock merged together with intrigue and both felt like jolts radiating in all directions on her body. Her sudden distraction was enough for him. With one swift move, he snatched the half-full glass she had been holding all along and quickly put a big distance between them with only two wide strokes.

"Not fair, Sousuke-kun!" Gou splashed water to his direction. She knew well trying to catch up with him in a swimming pool would be a lost battle before it even started. Sousuke cracked a lopsided smile at her and brandished his unusual trophy in the air, before ascending the pool stairs.

Gou inhaled sharply. He was stark naked.

She wondered why she hadn't noticed all this time he had been wearing only his birthsuit. It made sense he had brought no swimsuit with him, since Sousuke had come to her little private birthday party straight after finishing his patrol shift. And now he was gracing her with a full blown view of his chiseled rear. Being a huge muscles zealot all her life, and yet, she mulled how she had never properly appreciated that part of a male body. Especially Sousuke's tanned and strong, well toned gluteal muscles. Grateful to Gods for the water's presence, Gou went for a long dive to cool down her hormones.

Sousuke wrapped a towel around his waist and spread his body on a sun lounger made of bamboo. Earlier scenes , all puzzle pieces of a fiery evening dedicated to their own party of three , replayed behind his heavy lids. Rin's return had undoubtedly sparked their lives into motion, even for a night only. They had been treading around routine like zombies for so long that they had almost forgotten how restless was the blood pumping into their young veins. A soft breeze titillated Sousuke's naked skin, drying up all the last, little droplets scattered around his well shaped body. He had let Rin, the catalyst of his life, walk away from him twice in the past. And he was about to watch him doing it once more.

Another sun lounger next to him welcomed the weight of its new enjoyer with a low, creaking sound. Sousuke smirked.

"Tough night, huh?"

"Idiots.." Rin snorted while making himself comfortable "no matter how many times I tell them, they still manage to screw up my schedule. Tomorrow I'm starting training as soon as I land in Australia and , for some reason, they had to stick in the photoshoots I've arranged for later this week."

"Someone's mistaking you for an octopus, shark-boy."

"Idiots..."

Dressed in a pair of expensive, linen pants , topped by a white polo shirt and matched with brown, leather sandals, Rin was sporting the cool look of the social climber in an Oscar-worthy manner. Clad in brands and luxury almost appeared natural on him, Sousuke had to give him that. However, he was certain that this newfound lifestyle of his childhood friend didn't worth the sacrifices he had forced himself into.

"So...what do you think?"

"About what..."

Rin rolled his eyes. "Earth to Sousuke, where have you been for the past five hours? About...this!" he finished his words with a gloating smile and raised his arms, embracing the grandeur of their surroundings. Sousuke cast around the same aloof glance he would use to inspect a trashed can on any ordinary alley.

"Well, it looks like selling your body to a woman at your mother's age paid out. As long as her husband stays in the shadows."

"Actually, that jerk pays for everything she asks. Plus, I discovered he has an interesting fancy for redheads." Rin chuckled "They own places like this villa all over Japan and Australia. But, most importantly, they have connections. You are looking at the next cover of the top sports magazine in Melbourne. Not to mention I'm packed with relays for the following months. "

Sousuke turned his head slightly at him and greeted Rin's boasting with the same unimpressed face that used to drive the redhead mad when they were teenagers.

"You should come back to the force" he finally said in such a deadpan voice, that Rin looked at him incredulously for a moment before bursting into wild laughter.

"Are you fucking with me?"

Sousuke held his friend's crimson gaze for a while but remained silent. Reminisching about his childish habits , Rin clicked his tongue and let his eyes travel to the private pool before them. As night advanced, the velvet darkness and the artificial lightning had turned the waters into a sea of an ethereal cobalt . There, within its depths, like a modern Ariel straight out of some magical Disney world , Gou was savoring the night with a delicate swimming ballet. Sousuke mirrored Rin's reaction and they both stayed hushed for a moment, allowing mesmer to settle in their souls.

"My little princess...she has grown beautifully, hasn't she?"

"Tell me about it..."

Slowly, Gou stepped out of the pool , letting the water cascade down her appealing curves. Oblivious to the two sets of eyes preying on her feminine moves, she flipped her long , burgundy hair, sending hundreds of droplets into the balmy air.

"Her swimming skills have improved. My Gou is maturing into one fine, young woman."

"Really, how would you know?"

Rin rolled his eyes. "Oh Lord, here we go again..."

"You are barely here, Rin."

"Watch it, Yamazaki." Being called a shark for a reason, his sharp teeth gleamed under the moonlight, but the tall brunette shrugged him off. Meanwhile, Gou was waving at them from a nearby table. Her half eaten birthday cake – a strawberry shark with chocolate sprinkles - was still decorating its surface among used plates and delicious leftovers, but it was the open champagne bottle the young siren was aiming at. She proceeded in filling a new glass with the bubbly liquor, much to the boys' dismay.

"Exactly how many champagne bottles did you open?"

"I gave her the key to the cellar" Rin shook his head.

"Onii-chan! Sousuke-kun!" Gou exclaimed joyfully as she approached them. However, booze is the best advisor for lack of caution and she ended up tripping over a pair of flip flops. Instantly, Sousuke sat up and darted to her aid, but it was Rin who caught her small frame safely in his arms and helped her settle next to him. Overlooking her own staggering, Gou giggled at them amused.

"You boys are such a sight to behold, you should have seen your faces!"

"And you'll be yourself quite a sight soon at this rate. You won't need this anymore." Rin yanked the glass away from her and quickly gulped down its content, before sending it flying over the pool.

"Onii-chan!" his sister protested and , in return for his audacity, pinched him hard on his thigh.

"Fuuuuck Gou!" Rin winced in pain.

"It's Kou"

"Seriously? You still whine about that?"

"Listen , onii-chan. I am 18 years old now. You have no right to tell me what I can or cannot do."

"Yeah yeah. You are still my kid sister, underneath it all."

"I am not a kid!"

"Wanna bet? Then, why you still react like this?" And with that line, Rin charged her , catching her off guard. Locking her wrists together with one hand, he started tickling every inch of skin he found unguarded , forcing his sister into an endless series of giggles and sweet objections. She was a soldier of her own though and she managed a couple of bites on his intrusive hands, lessening his tight hold on her. Neither of them the one to back down, they continued assaulting each other in a medley of garnet hair, heartfelt cackles and teasing remarks, with Sousuke always as the chaperon admiring their boundless game. He thought that some unknown deity must have thrown him back a decade, at a time they were all careless kids. It seemed as if not a single day had passed. Sousuke smiled genuinely; those two would be his death one day.

Slowly catching their breaths again, as their little play died out, the Matsuoka siblings remained embraced and turned their attention to their athletic companion. But, although Rin's fiery scarlet met Sousuke's glowing teal , Gou's intrigued stare fell lower , on the smooth and tanned muscles of the handsome police officer. And it didn't go unnoticed by the hound she had for a brother. A mischievous glint sparked inside Rin's eyes and Sousuke knew well the redhead was up to no good. He propped his chin on his sister's shoulder and gently interlaced his fingertips with her soft hair.

"Oi, Sousuke..." he cleared his throat nonchalantly "...you seem to keep yourself quite fit. Heck, perhaps you've surpassed me now. What you think, Gou?"

"Your body is always the best, onii-chan."

"Naturally. But I keep up with hard training while he has quit swimming. I bet he should thank the police workout for this . His muscles are all buffed up. Right Gou?"

"Well, yes, but Sousuke-kun's muscles have always been exceptional" Gou softly admitted and , the next second, couldn't suppress the wild blush colouring her cheeks.

Rin grinned wickedly. Sousuke swallowed hard.

"Isn't that right , sis?" he leaned in , his whisper a provocative caress through her ear "..You checked those triceps out too, didn't you? He likes to stretch them a lot. And what about those golden pectoral muscles? Have you seen how they twitch everytime he breathes in?"

He was pushing her in a trance and it was working. Her crimson eyes roamed shyly on Sousuke's exposed body, resting on every firm muscle her brother was glorifying. Male bodies had always been her weakness ever since she could remember herself and she kept feeling like a hungry child in front of a giant , luscious candy. Sousuke's candy for the matter.

"Touch him..." Rin breathed out.

Sousuke thought this was probably the right time for him to butt in, but the feeling of a silky hand hesitantly touching his inflamed skin , made his mind freeze and his tongue stay tied. Under her timid touch, his muscles tensed and she bit her lower lip at the sensation, before daring to stroke his broad chest with more pressure. Rin couldn't contain his bliss over his impeding triumph. His right hand trailed up his sister spine and came to rest on a very sensitive spot on her nape , a spot he knew damn well it caused erotic eruptions through her body. Slowly, his long fingers massaged her nape and Gou felt a carnal mist piling up behind her now heavy eyelids.

"I'm gonna give you another gift tonight, Gou. Let's call it a gift of sin " his suggestive murmurs seemed to echo from somewhere very far . "Kiss him"

Just like a puppet pulled by its strings , Gou leaned over the tall brunette , completely surrendered to her puppeteer's command. Sousuke's eyes widened. He placed his steady hands on her shoulders , firmly keeping her inches away from his electrified face . Glancing over her shoulder at Rin, his mouth formed the word "bastard" , before letting his sapphire pierce through Gou's last defences.

"Are you sure about this?" he asked in the most honest and affectionate way. Gou lowered her gaze in guilt; for she was no fool. Despite her brother's ministrations, she would be a liar if she ever claimed she hadn't been lusting after her childhood friend all this long, if she ever refused she had been jealous of the nights Rin secretly spent with him over her teenhood.

"Yeah, I..."

She never managed to finish whatever feeble justification she was about to say. Sousuke's lips came crashing on her own, leading her to a feverish passion she could never believe he had kept dormant all along. His kiss turned to an open mouth battle of blazing tongues and merciless bites , as he pulled her further into his arms. Instictively , she straddled his waist and let her hands explore without any more inhibitions the well sculpted muscles she so adored, all the while switching between sucking his lips and licking his jawline. Sousuke's solid manhood had already stretched the towel covering whatever modesty he had left, and the fact that Gou , feeling how hard he already was, was rolling her hips in perfect response , did not help at all.

"Damn..." he cursed, breaking their mouths apart.

Rin stood behind Gou's back like a mad inventor pleased with his new creation. He offered a wink at Sousuke and swiftly took off his polo shirt. He grabbed a handful of Gou's flowing red mane and gently pulled her head back, compelling her to straight up her spine. His mouth found her shoulderbone and he nibbled her smooth flesh all the way up to her neck.

"Let's show him what he has been missing..."

Effortlessly, his skillful fingers pulled the straps of Gou's bikini top. The flimsy undergarment slid off her torso, revealing a perfectly shaped bosom with two juicy and erect rosebuds. Sousuke bucked up his pelvis in response. His hands cruised up her abdomen and cupped each firm breast. He was not surprised when he witnessed Rin's hands coming from behind Gou's body to rest on his own, lightly urging him to squeeze her harder. And he did. The reward of their synchronized motions was a series of raunchy moans escaping the young woman's rosy lips.

"This towel has to go." Rin pointed at the offensive barrier between her and Sousuke, while sucking her earlobe.

"You talk too much, onii-chan"

Gou pulled away the towel and moved back a bit to marvel at the impressive sight of Sousuke's erection. Rin chuckled at her reaction.

"I guess you both have been missing alot."

Gou took his member in her hands. It was heavy and solid, a physical feature worthy of an alpha male. She gave it a few strokes, testing the waters, and soon guided it inside the warmth of her mouth. Rin pulled her bangs away, granting Sousuke with a thrilling view of his sister's aroused face, as she licked and teased his tender flesh. She had a problem swallowing him whole, but she balanced her inexperience with such length by working her velvet tongue and gracing him with the most tantalizing sensation he had felt in years.

"Here, let me show you."

Gou felt Rin's hot breath next to her burning cheek , as the young swimmer leaned closer. She watched with newfound curiosity while her brother closed his mouth with ease around Sousuke's throbbing shaft. With each experienced sucking, he was relaxing his jaw even more and , inch by inch, he soon devoured him to the hilt. Meanwhile, Sousuke had folded his left arm behind his head, effectively propping it up his palm to maximize his enjoyment. Despite his inner growing delight, he watched the garnet maelstrom around his crotch quite collected. His thick fingers reached the siblings' hair and fondled it lovingly, unable to distinguish them within this colour disarray. Truth was garnet had always been his one and only weakness. They were taking turns now in blowing him, Rin's motions harder and ecstatic, Gou's softer and playful. Yes, those two would surely be his death one day.

"Stop"

Sousuke's stern voice interrupted them abruptly. Rin cracked an impish smile while sweeping the precum off his lips , but Gou blinked a few times not realising what was happening. Sousuke slipped away from their embrace and stood up. He was all fired up but the expression on his face was rather serious.

"What's going on? Something's wrong?"

Taking Sousuke's position on the lounger, Rin turned on his back, luring his sister in his secure arms.

"Nothing is wrong, my little Gou. It's just that the big boy here has a special preference on the bottom end..."

Suddenly, Gou felt two large hands encircling her waist and , effectively , holding up her rear. She craned her neck sideways and looked anxiously over her shoulder . Sousuke had already positioned himself behind her , the tip of his member lightly brushing against the bikini fabric covering her anus. Her heart started pounding erratically inside her chest the moment their gazes crossed; primal lust had darkened several shades the once teal of his eyes. Rin cupped her face lovingly and, slowly ,turned her focus back on him.

"Don't be nervous. Relax. I'm here."

And that's what she only needed to hear. Her brother's soothing voice in her ears, his protective arms envelopping her tenderly, his long fingers pacifying her shivering body. He held her dearly while Sousuke pulled aside her bikini bottom and, using his saliva as lubricant, slowly entered her forbidden back door. He held her dearly while the taller male established an emotionless, steady pace ,thrusting and digging his fingers on her hips' flesh. At first , she yelped under the burning sting that spread inside her , but soon her body adjusted to the rhythm Sousuke had set and erotic fervor built up in her private parts. Helping her reach her own cloud nine, Rin's hand sneaked below her now sweaty torso , seeking the sweet epicenter of her sexual discomfort. Parting her satin folds, he began rubbing her with prowness, while she clung on him as tightly as she could. Gou was almost lost in an ocean of tingles and emotions parading through her body, when she felt Sousuke's weight on her back. The dark haired policeman leaned over them, and though he kept his pressure deep inside her under absolute control, his very core seemed focused on one man alone; her brother.

"You'll come for me too"

"Sous-.."

Rin didn't have time to object. Sousuke's hand dived between the shark's toned body and Gou's feminine curves , and pulled Rin's vibrating penis out of his linen slacks. Not wasting any time, he started pumping the redhead vigorously , harmonizing his hand's motions with his pelvis' thrusts. Trapped between two robust male bodies, Gou watched in lecherous rapture as Sousuke leaned in and possessively captured Rin's mouth , all the while keeping up with both of them. Dazed by her own euphoria, she buried her face further into her brothers' neck, while his moans echoed through the scorching night.

About an hour and a half later, a buzzing sound sliced the setting stillness. Sousuke sluggisly reached an arm out and picked up the beeper resting on the floor. In his arms, Gou stirred in her sleep.

"Onii-chan..."

 _He even dominates her dreams._ Sousuke shook his head pensively. Quietly , he tried to detatch himself from the young girl nesting beside him, but his movements only made her grip on him grow tighter.

"Where's onii-chan?"

"Gou..."

Her eyes were slightly open now but she seemed to be walking the line between sleep and consciousness.

"Your onii-chan's fine, Gou. He has been in the pool for the past hour, racing against his own self. I wonder where he finds all the andrenaline."

Gou nodded. Still, she didn't loosen her grip. Sousuke sighed.

"I have to leave, Gou. That was a call from the police station. I have to.."

"Stay, Sousuke-kun...and make my onii-chan stay too...please..."

Sousuke closed his eyes for a second and swallowed the knot hampering his throat. Looking down at her, he noticed that Gou had already delved back into slumber. This time he managed to slip away from her and stand up. For a moment he remained silent , taking in her angelic sleeping form. Then, his thoughts escaped his mind in the shape of whispers.

"Go back inside, Gou. It's always cold in the morning hours."

He leaned in to place a sweet kiss on her lips, but he stopped. Instead, he let his mouth travel north and softly touch her temple. Just like he used to do when they were children. Within three minutes, Sousuke had put on his blue uniform and was fastening his belt at the edge of the pool. Suddenly, a triumphant shark emerged from the depths, splashing water all around him.

"Aha! Almost four minutes and without any practice!" Rin roared proudly and brandished a stopwatch in the air "At this rate, I'll be able to break Haru's old record and hold my breath underwater even longer...oi, Sousuke! Why you are all dressed up?"

"Have to head over to the police station. Some minor issue came up, but I'm needed"

"Oh...well, hold on a second. I'll walk you to the car."

They walked up to the street in silence, with Rin occasionally commenting on the expensive marbles or the various flowers adorning the front yard. A couple of steps before the parked police car, the redhead came to a halt, annoyance riling him up.

"Look, Sousuke. If you have something to say, better spit it out now. Just stop acting like a walking mystery all of a sudden, I put my best effort for you to have a great time tonight, so what the hell..."

The rest of his anger was muffled as Sousuke's mouth came crashing on him, without any warning. Rin was startled for a second, however as the brunette's lips claimed his own , forcefully demanding access , he groaned against his friend and gave in. The kiss started violent and needy, but it soon blossomed into a choreography of emotions and sweet nostalgia. It was Sousuke that broke their liplock first and Rin followed his mouth still charmed , like a kitten mesmerized by milk. They rested their foreheads against each other and breathed in heavily.

"Come back to us, Rin" Sousuke finally spoke , his eyes sinking into crimson. "Leave this high class bullshit, quit running away and return where your friends and family are. Haruka and the rest miss you, Rin. Their team has never been the same since you left. Even the guys at the force still talk about you. Come back, Rin. Stay with me...and Gou...can't you see what your absence is doing to her?"

It was Rin's turn to break apart from his friend. He put a few steps between them before raising his head to look at his old mate. Pure exasperation emanated into waves though every feature of his.

"Have you got any idea what you're asking me? Have you? Quit my current life and do what? Rot in this place? Return to Haru , Mako, Nagisa and do what? Swim just for the sake of swimming? You don't get it. I have nothing to show them anymore! Everyone chose their path, I would only drag them back into the past! Coming back to the force, such a joke...Were you even there when they laughed behind my back? You know damn well, Sousuke. Damn well! Why you think I left in the first place? Will you bear the weight of telling my mother? Will you tell her that her son has been in love with his best friend who , actually, happens to be a man? Or even better, that I am the freak who has been banging his own sister?!"

All that Rin had been keeping bottled up for years, had just come howling into a relentless torrent, sweeping away everything before its reach.

"Ok."

Rin was still boiling and trying to bite back his words, but Sousuke had already resumed his usual cold and impenetrable stance. He covered the last steps towards the police car and when he opened the door, he paused for a second.

"Stay with Gou till you leave tomorrow. You may give her all the gifts in the world, but it's you she only ever needed."

Rin watched the car till it vanished at the end of the road and its engine could not be heard anymore. Turning around, he shoved his hands in his pockets and noticed a light coming from one of the rooms inside the villa. His eyes wandered up the windows until they finally rested on Gou's smiling face behind the glass, her youthful beam reaching out to him.

And his heart skipped a beat.

 **The End**

Thanks for reading, reviews are appreciated. **  
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